Editorial
On the Spirit of Problems and Tests
Резюме. By solving problems and tests the practical skills of the students are exercised. However the pure mathematical exercises should be avoided because they are often a source of boredom for the learners. Any problem should have a “spirit” – something from the daily-life or something amusing. Then the attention of the students will be kept and, therefore, the educational goals will be achieved.
S. Manev
Влезте в системата, за да прочетете пълната статияCurriculum Matters
Chemistry Training in Bulgarian Secondary School and International Chemistry Olympiad
Резюме. International Chemistry Olympiad (IChO) is the most representative forum of young chemists from all over the world, where Bulgaria participates regularly. The results of the Bulgarian team in IChO competitions are getting worse in last years. A main reason for that is the big difference between high requirements of the IChO syllabus and insufficient chemistry training in Bulgarian secondary school. Members of the Bulgarian team for IChO are nominated among winners in National Chemistry Olympiad (NChO) which are based on chemistry in the Bulgarian secondary school. If the IChO syllabus is put in the background of NChO as well, then training of candidates for the team will become better. New system for conducting of NChO is proposed.
G. Pekov, D. Tasheva, P. Tsanova
Problems
XXXVIII International Chemistry Olympiad: Problems with Solutions
Резюме. The paper lists problems (practical and theoretical) of the last International Chemistry Olympiad (XXXVIII IChO), and the solutions of the theoretical problems. A Critical review of presentation of the Bulgarian team in this competition is given.
G. Pekov, D. Tasheva, P. Tsanova
From the Research Laboratories
Analytical Study of Amphetamine and Methamphetamine by Reverse-Phase High-Performance Liquid Chromatography Method
Резюме. Amphetamine and methamphetamine were tested compounds using RP-HPLC method. On the basis of analytical studies, a new procedure for the chromatographic separation and determination of analyzed drugs was completed in about 5 minutes. The samples were eluted isocratically using a mobile phase consisting of acetonitrile and ortho-phosphoric acid (pH 2.1) [15: 85, v/v] at a 1.0 mL/min flow rate, with UV (205 nm) detection and temperature at 40oC. The described procedure allows the quantification of amphetamine and methamphetamine with adequate linearity, reproducibility and accuracy in the concentration interval 5.0 – 500.0 microg.mL-1. For both compounds, the limits of detection were 0.5 microg.mL-1. The utility of the described assay was tested by determining the analyzed compounds in seized tablets.
V. Pavlova, S. Petrovska-Jovanovic
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